(a) Field of the Invention
The present invention relates to a positioning method and a positioning apparatus, and more particularly, to a positioning method measuring a position of a user based on reliability, and an apparatus thereof.
(b) Description of the Related Art
Recently, personal digital assistants which may provide positional information have been spreading rapidly, and the number of services which may provide positional and geographic information through the portable digital assistants are also quickly growing. To keep up with the tendency, attempts to smoothly provide a seamless positioning service which is a combination of an absolute positioning solution such as a global navigation satellite system (GNSS) and a WiFi positioning system (WPS) using WiFi information, a dead reckoning solution measuring a relative position such as an inertial navigation system (INS) having a multiple sensor structure, and the like, breaking from the existing services which provide only outdoor positional information, have continued.
A method for increasing positioning reliability by estimating current position related information (for example, whether a user is indoors or outdoors, and the like) affecting the calculation of reliability of an absolute position used for the dead reckoning and positioning-related resource information which are acquired by these systems and using the position related information for the dead reckoning has been frequently researched.
However, the method for determining a current position of a user using signals or distribution characteristics of positioning related resources such as the commonly used GNSS or Wi-Fi has accuracy changed depending on situations, and therefore hardly ensures the stable positioning reliability.
The GNSS-based positioning has relatively high reliability in the environment such as an open area and provides positioning quality of relatively high accuracy, and therefore has been considered as the positioning service which is most widely used. However, since it is difficult to acquire the GNSS signal in an environment such as the interior of a room, a basement, and downtown buildings, in terms of service characteristics, there is a drawback in that the services may be restricted. Further, in the case of an urban area which is becoming a main target of the positioning service, as the user approaches a building, influences of refraction, reflection, interruption, etc., of a signal are serious, such that an error may be increased and thus the reliability may be reduced.
Therefore, researches to provide a GNSS service to a boundary area or the interior of a room using a pseudolite method and the like have been frequently conducted, but have restrictions in public spreading and commercialization.
Meanwhile, the Wi-Fi based WiFi positioning system (WPS) is a method of estimating the position using an access point of a wireless local area network (WLAN) network, and estimates a position by allowing a terminal to measure a signal strength transferred from APs and calculate a signal transmitting distance depending on signal attenuation. The method is very effective in a downtown area or an interior of a room in which the density of APs is high. However, in the case the exterior of a room or the suburbs in which the density of APs is low, there is a drawback in that the reliability is greatly degraded and the performance thereof shows a big difference, depending on the distribution characteristics of the APs.
To solve the above problems, many researches to provide the positioning service by continuously connecting the positioning technologies having different service areas and characteristics have been conducted. As the representative method, there is a method of estimating positioning services having a dominant quality for each region by using the signals and the distribution characteristics of each service resource, and when the user continuously moves in a region in which positioning resource distribution characteristics are different, providing the positioning service having higher reliability and higher accuracy based on a service transformation boundary point. Further, there is a method of providing a seamless positioning service by introducing a third information transfer means, such as a beacon, which radiates a signal capable of confirming the positioning service to the transformation point of the region.
However, the method of using the signals and the distribution characteristics of the resources has a measurement value which is excessively changed depending on the environment in which the user is located to cause a large error, and makes the service region transformation time of the user and the transformation time when the positioning service is provided different to increase the transformation time estimation error, thereby reducing the reliability. Further, the method of using a third information providing means needs to construct an additional transfer service therefor in advance, which acts as restriction to provide actual services.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.